Beware Battery Maintainers

[ukkid35]

They can give a false sense of security

I have been using a Lidl Ulgd 3.8 amp, which has a nice clear digital voltage readout

It will ensure the car starts first time, but go for a drive, stop and try to start a hot engine, and it won't turn over

Luckily waiting ten mins for the engine to cool somewhat will allow the car to start

When I got home I tried restarting the car with the maintainer connected to see that the voltage dropped to 6.3v when I attempted to start the engine

In comparison the cold start voltage was 10.8v,

The battery itself was 11 months old, and I actually managed to get a replacement under warranty from EuroCarParts yesterday - Result!

[ukkid35]

TwinKam said:

My battery of choice from them for my customers is Exide, and I have never had one fail under warranty, though even that might not be the best choice for a Cerb.
Rik

The Lion was an emergency purchase

I did have an Exide in my other car and it did exactly the same as the Lion

I could leave the Exide on the maintainer, start it with no issues, go for a drive, and then become stuck when I need to restart

The issue isn't the quality of the battery, that just determines how quickly they fail

The problem is that a maintainer has repeatedly fooled me into driving a car with a failing battery, and then getting stuck as a result

[ukkid35]

RUSSELLM said:

Out of interest, is that digital display telling you the voltage that the charger is sending out, or is it attempting to read a hot battery ?

You can connect it and see the battery voltage without switching on the charging circuit

I can't believe it's taken me so long to check the voltage drop when starting

[ukkid35]

Jhonno said:

Perhaps the Lidl charger is damaging the cells if you have had it happen twice to new batteries, including the better quality Exide? A battery, especially one kept on trickle charge shouldn't fail after 11 months..

Sorry, I should have mentioned that the Exide was probably five years old

But the maintainer still fooled me in to thinking it was fine

[ukkid35]

tejr said:

This is a really good technical review on amazon about how all battery conditioners are not the same - even the staged ones.

That is really great info thanks, I'm really tempted to buy a CTEK

But I still don't understand how the CTEK is going to tell me that: sure the battery will start the car, but you won't be able to restart later

Or, will it prevent me from starting the car in the first place?

[ukkid35]

notaping said:

This sounds more like a starter heat soak problem than a battery problem.

Except it starts fine if I attach my uber cheap lithium battery booster

This but more like £25

https://www.ebay.co.uk/itm/253527177234

More importantly the voltage drop gives away the fact that it's a battery issue not a starter issue

[ukkid35]

notaping said:

When you attach the booster you are effectively increasing the available current to the starter. It does not explain why the starter needs more current when hot. The only explanation for this is a change in the condition of the starter - ie. getting hotter.

Yes you are absolutely right, the hot engine/starter is more power hungry, but that is not the issue

I've completely failed to explain that the issue I'm concerned about is that a battery maintainer can mask the fact that a battery is no longer viable

It may be able to start a cold engine immediately after being connected to a maintainer for a week or two

But ask the battery to start an engine repeatedly, over a short period of time, when the engine is up to temp, and it doesn't want to know

Probably because the effective capacity is now more like 7Ahr rather than the original 70Ahr

[ukkid35]

QBee said:

Yes, you could well have a knackered battery, but your problem to me reeks of knackered old, under strength, starter motor cable.

I had two knackered batteries, a Varta D39 and a Lion 078, they both behave in exactly the same way, but the Varta is several years older

The point of my original post was to warn people that using a battery maintainer has fooled me in to driving a car that won't restart subsequently

This happened to me a week ago on the upramp of a motorway junction at rush hour, with no hard shoulder

I spent 15 minutes watching cars drive up behind me at speed, despite having hazards on, completely oblivious to the fact that there was a big space ahead of me, and I wasn't going anywhere

It is almost irrelevant whether there are flaws in the starter circuitry, because eventually all batteries fail, and my experience is that battery maintainers do a great job of allowing a car to start even with a battery that is completely fubared

So what I was trying to say, with very little success, is that battery maintainers can allow a car to start - once, and then leave you marooned in a potentially horrible situation